• 제목/요약/키워드: Euphausiids

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겨울철 동해 북부 난바다곤쟁이류(Euphausiids)의 주야 수층별 분포 (Day-Night Vertical Distribution of Euphausiids in the Northern East Sea in Winter)

  • 이보람;이현규;지환성
    • 한국수산과학회지
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    • 제56권2호
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    • pp.259-264
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    • 2023
  • Day-night vertical euphausiid distribution was investigated at three stations in the East Sea using a Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS). Three euphausiid species were recognized. Euphausia pacifica was more dominant than Thysanoessa longipes. Euphausiids were collected at Station 1 at night, Station 2 at sunset, and Station 3 during the daytime. At Station 1, calyptopis and furcilia stages were concentrated from the surface to 30 m and 20-40 m, respectively. Juveniles and E. pacifica were distributed in strata shallower than 30 m. At Station 2, calyptopis and furcilia stages were dominant in strata from the surface to 40 m. Juveniles were not recorded in strata at 30-100 m. However, E. pacifica occurred in these strata. At Station 3, calyptopis and furcilia stages occurred in the upper 40 m of strata. E. pacifica was distributed deeper than 100 m and rarely occurred above 100 m. The furcilia stages weakly migrated, whereas the calyptopis stages did not. Juveniles and E. pacifica showed a clear migration pattern. Vertical distribution of euphausiids in the northern East Sea varied by life stage and time of day.

2016년 한국 근해 난바다곤쟁이류의 시·공간적 분포 (Spatio-Temporal Distribution of Euphausiids in Korean Waters in 2016)

  • 이보람;박원규;이해원;최정화;오택윤;김두남
    • 한국수산과학회지
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    • 제54권4호
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    • pp.456-466
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    • 2021
  • The distribution and abundance of euphausiids were investigated in Korean waters in 2016. Euphausiids were sampled with a Bongo net. A CTD (Sea Bird Electronics 9 plus) measured the water temperature and salinity while sampling. Mean water temperature ranged from 4.2-31.0℃. The highest temperatures occur in September and lowest temperatures in February. The mean water salinity ranged from 27.9-34.8 psu, with the highest salinities in March and lowest in September. Euphausiid species in group W consisted of four species. Among the euphausiid species, Euphausia pacifica was the dominant species with peak densities in September. The E. pacifica from group W was distributed in the bottom cold water during summer when a thermocline was formed. Five euphausiid species occurred in group S. E. pacifica and E. nana were the dominant species. In group S, E. nana was located in the warm and saline Tsushima Warm Current, a branch of the influential Kuroshio Current. Five euphausiid species occurred in group E. E. pacifica and T. longipes were the dominant species. In group E, E. pacifica and T. longipes were distributed in the deep and cold waters, these species prefer low water temperatures and perform vertical migration. The distribution of euphausiids in Korean waters were highly influenced by mass water characteristics, such as temperature and salinity.

우리나라 서해에서의 해양환경변화와 동물부유생물의 장기간의 출현량 변화 (Variations of Marine Environments and Zooplankton Biomass in the Yellow Sea During the Past Four Decades)

  • 최정화;박원규
    • 수산해양교육연구
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    • 제25권5호
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    • pp.1046-1054
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    • 2013
  • Spatial and temporal variations of sea surface temperature (SST), abundances of copepods, euphausiids, amphipods, and chaetognaths were investigated in the western waters of the Korean Peninsula. Zooplankton and SST were monitored at 63 stations arrayed in six transects ($124^{\circ}00^{\prime}-126^{\circ}30^{\prime}E$, $34^{\circ}00^{\prime}-37^{\circ}00^{\prime}N$) in February, April, June, August, October, and December during 1978-2010. In general, SST increased $0.7-3.8^{\circ}C$ during the last three decades with spatio-temporal variations. SST was lowest in February and highest in August. SST was highest in the northernmost transect and declined gradually along transects to the south. The general pattern of interannual variations of SST was similar to the global pattern, which has been increasing. Trends of abundances of all zooplankton groups slightly increased interannually and peaked seasonally in June and August, except chaetognaths, which fluctuated around the long-term mean value with a seasonal peak in August and October. Abundances of zooplankton groups were highest in the northernmost transect while those of euphausiids were highest in the southern transect. We discuss the distribution patterns of SST and zooplankton groups in relation to oceanographic characteristics in the study area.

동해 연안에 출현하는 도루묵(Arctoscopus japonicus)의 위내용물 조성 (Diet composition of the sandfish, Arctoscopus japonicus in the coastal waters of East Sea, Korea)

  • 강다연;고아름;정재묵;백근욱
    • 수산해양기술연구
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    • 제55권4호
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    • pp.320-326
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    • 2019
  • The diet composition of Arctoscopus japonicus was studied using 448 specimens collected in the coastal waters of East Sea, Korea. The size of the specimens ranged from 6.2-25.3 cm in total length (TL). A. japonicus were fed mainly on amphipods that constituted 76.1% in IRI. Euphausiids were the second largest prey component. The diets also include small quantities of crabs, copepods, mysids, cephalopods, monogeneans, and fishes. A. japonicus showed ontogenetic changes in feeding habits. Smaller individuals (6-10 cm, TL) fed mainly on amphipods. The proportion of amphipods decreased as body size increased, whereas the consumption of euphausiids gradually increased (10-14 cm, TL). As the body size more increased, the proportion of amphipods increased whereas euphausiids decreased (14-26 cm, TL).

Density estimation of euphausiids and copepods by using a multi-frequency method

  • Woo Seok Oh;Geun Chang Park;Jung-Hwa Choi;Hyoung Been Lee;Kyounghoon Lee
    • Fisheries and Aquatic Sciences
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    • 제26권12호
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    • pp.689-697
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    • 2023
  • This study used a multi-frequency acoustic method to assess the density and spatial distribution of dominant zooplankton, euphausiids and copepods, which are representative species of the zooplankton immigrating the sea around Republic of Korea. Acoustic surveys were carried out in the East Sea and South Sea from June 16 to 29, 2017, using the research vessel Tamgu 20th from the National Institute of Fisheries Science. From the results of the acoustic survey, the distribution of euphausiids was relatively higher in the East Sea than in the South Sea. Additionally, although the distribution of copepods was low in all areas, they were abundant in certain areas in the East Sea and the southern area of the Jeju Sea. Euphausiid and copepod density was estimated to be 1.2 g/m2 (CV = 19.1%) and 2.8 g/m2 (CV = 23.5%), respectively.

부산 주변 해역에서 채집된 불볼락(Sebastes thompsoni)의 식성 (Feeding Habits of Sebastes thompsoni in the Coastal Waters off Busan, Korea)

  • 허성회;남기문;추현기;백근욱
    • 한국수산과학회지
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    • 제41권1호
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    • pp.32-38
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    • 2008
  • We studied the feeding habits of Sebastes thompsoni based on 421 specimens obtained in monthly collections between January and December 2005 in the coastal waters off Busan, Korea. S. thompsoni was a crustacean feeder, and consumed mainly shrimp and euphausiids. Its diet also included small quantities of amphipods, cephalopods, and fish. It showed distinct ontogenetic changes in feeding habits. Smaller individuals (14-17 cm standard length (SL)), mainly consumed euphausiids. The portion of these prey items decreased with increasing fish size, and larger individuals (>20 cm SL) consumed mainly shrimp such as Leptochela sydniensis.

고리 주변 해역에서 채집된 황아귀 (Lophius litulon) 유어의 식성 (Feeding Habits of Juvenile Lophius litulon in the Coastal Waters of Kori, Korea)

  • 백근욱;허성회
    • 한국수산과학회지
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    • 제36권6호
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    • pp.695-699
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    • 2003
  • We examined the stomach contents of juvenile Lophius litulon, which were collected monthly in the coastal waters of Kori, Korea from January to December, 1996. L. litulon was a bottom feeding carnivore which mainly consumed fish, euphausiids, sagittoids, and shrimp. Its diet also included small quantities of copepods amphipods, and stomatopods. It showed distinct ontogenetic changes in feeding habits. Small individuals (1-2 cm SL) mainly preyed on sagittoids and euphausiids. However, individuals eve, 3 cm SL mainly preyed on fish and shrimp.

동해에 출현하는 기름가자미(Glyptocephalus stelleri)의 위내용물 조성 (Diet of the Korean Flounder Glyptocephalus stelleri in the Coastal Waters of the East Sea of Korea)

  • 성기창;고아름;남기문;정재묵;김정년;백근욱
    • 한국수산과학회지
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    • 제52권4호
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    • pp.430-436
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    • 2019
  • The diet of Glyptocephalus stelleri was studied using 475 specimens collected in the coastal waters of the East Sea of Korea. The specimens ranged from 6.8 to 43.4 cm in total length (TL). G. stelleri was a crustacean feeder that consumed mainly euphausiids [percent index of relative importance (%IRI)=63.7%]. Polychaetes were the second largest prey component. The diet also included small quantities of bivalves, copepods, amphipods and shrimps. Individuals smaller than 15 cm TL fed mainly on euphausiids. The proportion of euphausiids decreased as body size increased, whereas the consumption of polychaetes increased gradually.

한국 남해에 출현하는 전갱이(Trachurus japonicus)의 위내용물 조성과 영양단계 (Diet composition and trophic level of jack mackerel, Trachurus japonicus in the South Sea of Korea)

  • 김도균;성기창;진수연;서호영;백근욱
    • 수산해양기술연구
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    • 제57권2호
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    • pp.117-126
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    • 2021
  • Diet composition and trophic level of Trachurus japonicus were studied using 417 specimens collected by trawls, set nets and purse seine fisheries from March 2019 to February 2020 in the South Sea of Korea. The size of T. Japonicus ranged from 7.0 to 49.8 cm in total length. T. japonicus were a carnivore that fed mainly on euphausiids and pisces. In eddition, T. japonicus fed on small quantities of cephalopods, crabs etc. T. japonicus showed ontogenetic changes in feeding habits. The proportion of euphausiids decreased inversely proportional to body size whereas the consumption of pisces gradually increased. As body size of T. japonicus increased the mean number of prey per stomach and the mean weight of prey per stomach tended to increase, but the mean number of prey per stomach was not significantly different. As a result of the feeding strategy analysis, T. japonicus were specialized feeders with pisces and euphausiids as their dominant prey. The trophic level ranged between 3.57 ± 0.54 and 3.91 ± 0.65, and increased asymptotically with size of specimens. The average trophic level of the T. japonicus was 3.79 ± 0.61.

The diet of three commercial fishes based on stomach contents in the Yellow Sea

  • Heeyong Kim;Wongyu Park;Jung Hwa Choi
    • Fisheries and Aquatic Sciences
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    • 제26권10호
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    • pp.628-636
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    • 2023
  • Stomach contents of three commercially important species, anchovy (Engraulis japonica), small yellow croaker (Larimichthys polyactis) and yellow goosefish (Lophius litulon) were analyzed to investigate difference of prey between Spring and Fall. Trawl surveys for target fishes were conducted at 12 stations by the RV Tamgu-8 in the Yellow Sea-Korean side in Spring and Fall 2008 as a part of the United Nations Development Programme/Global Environment Facility (UNDP/GEF), Yellow Sea Large Marine Ecosystem (YSLME) survey. Stomach contents of 50 individuals of each species were analyzed to species level of prey, if the number of specimens was more than 50 for each species. Fullness and digestion condition of stomach contents were determined by five and six levels, respectively. In anchovy stomachs, 23 species in Spring and 15 species in Fall were identified, respectively. Stomach contents were mostly occupied by copepods and euphausiids, mostly Euphausia spp., calyptopis in Spring while by copepods and amphipods in Fall. In small yellow croaker stomachs, 23 species in Spring and 11 species in Fall were identified. Stomach contents were mostly occupied by copepods and euphausiids in Spring, but by only euphausiids in Fall. Total 368 yellow goosefish (151 in Spring and 217 in Fall) were captured, but stomach contents only in Fall were analyzed. Most of stomach contents were anchovy with small proportion of Hakodate sand shrimp, Tanaka's snailfish, Pacific cod, and miscellaneous things. The present research unveiled that main food items of plankton feeder were distinctly different by species and seasons in the Yellow Sea-Korean side, as coincided with previous reports.